This exchange may be of interest.
May 18, 2000 Post to the Prakash Ag BioView list, in response to message
Alan Shapiro questions the source and validity of the Charles
Margulis statement that herbicide tolerant soybean varieties, especially RR
soybeans, increase herbicide use measured on the basis of pounds applied
per acre. The statement is accurate and the source is USDA-National Ag
Statistics Service data on soybean herbicide use over the last several years.
For those unfamiliar with the basics of soybean herbicides and the
impacts of GMO/RR soybeans on use rates, the simple facts are these.
In the early to mid-1980s, most soybean herbicides were applied in
combinations, and at a combined rate between 0.75 to 1.5 pounds per
acre. These are sometimes today called the "traditional" soybean
herbicides or weed management systems (see below).
By the mid- to late 1980s and throughout the 1990s, the pesticide
industry developed and marketed dozens of new, low-dose soybean herbicides
in the imidazolinone and sulfonylurea classes. These products are applied
typically in the 0.05 pounds active ingredient per acre to 0.2 pounds per
acre range. Often, two active ingredients are required, resulting in total
per acre application rates of 0.1 to 0.3 pounds per acre.
To this day, some acres are still treated with the old
conventional herbicides applied at rates between 1.0 and 2.0 pounds per
acre, again mostly in combinations. In recent years about 15% of acres are
treated with trifluralin at about .9 pounds/acre and another 16% or so with
pendimethalin at .97 pounds per acre. These products are typically
supplemented with an application of another herbicide, and in some cases
are used prior to planting RR beans.
Along comes RR beans in 1996. Adoption has increased to over 55%
of acres, at an average rate of application of about .92 pounds of
glyphosate per acre per season (average about 1.3 applications per acre;
i.e. about one-third of growers use 2 applications). Roundup is typically
used in combination with other products, bringing average total herbicide
use per acre to about 1.5 pounds (see our forthcoming report for source of
these data). Many farmers using RR beans are applying over 2 pounds per
acre, a few apply less than 1 pound.
So, if you are a biotech proponent or Monsanto, you compare
herbicide pounds applied at the low-end of the Roundup Ready treated acres
distribution, i.e. at a rate of about 1 pound per year, to the small
percent of acres treated just with the higher-dose, older
products. Monsanto has prepared a document called "Chemical Reduction
Benefits of Biotechnology Crops, Compiled November 30, 1999." This
document is for the press, political leaders, and PR purposes and has been
widely disseminated. On the Roundup herbicide use and GMO-soybean front,
it states --
"In a Sparks Commodities, Inc. study conducted in 1996 and 1997,
in-season herbicide use in Roundup Ready soybean fields was shown to be
less than TRADITIONAL SOYBEAN FIELDS by an average of 26 percent and 22
percent respectively, over four regions of the United States."
This statement is probably true in a narrow sense but is also
creatively misleading if not down-right dishonest. What the statement
means is that there are soybean producers in each of four regions still
using the older, higher-rate herbicides, and compared to their weed
management systems, the "traditional soybean fields," herbicide use in RR
bean fields is less.
What the Monsanto materials do not say is that if the comparison
was instead to the average soybean field not planted to RR beans, or even
worse, to farmers using "modern, low-dose herbicides," the results would be
very different. In my review of the RR yield drag (accessible at
<http://www.biotech-info.net/RR_yield_drag_98.pdf>), I stated that Roundup
use is between 2 and 5 times greater measured on the basis of pounds
applied per acre, when the comparison is between the average field planted
to RR beans and most other soybean acres not planted to GMO
varieties. When compared to systems utilizing the really low-dose
herbicides, the Roundup ready fields require more than 10 times the
herbicide, but such a selective comparison would be analytically
dishonest. But I guess it all depends on what you feel the rules are and
whether everyone has to follow them.
Soon we will release a new report that very clearly shows that on
the average RR soybean fields, substantially more herbicide is applied when
measured on the basis of total pounds of active ingredient applied per acre
compared to the average non-GMO soybean fields. When a truly fair
comparison is made of average rates, the answer is clear.
There are many benefits to farmers of the RR soybean technology
despite the yield drag (recently confirmed by researchers at Nebraska),
greater reliance/use of herbicides, and the system's higher cost (compared
to some alternatives). But reducing herbicide use is not one of them.
To: AgBioView <AgBioView@listbot.com>
Date: Wed, 17 May 2000 13:50:18 -0400
From: "Allan D. Shapiro" <ashapiro@UDel.Edu>
Subject: herbicide use
AgBioView - http://www.agbioworld.org, http://agbioview.listbot.com
I have a question that I'm hoping someone subscribing to this list
answer. I am an Assistant Professor of plant biology at the University of
Delaware. Yesterday, at the request of a local (Delaware/Philadelphia)
radio station, I served as a guest on a radio talk show with the other
guest being Charles Margulis of Greenpeace's biotech division with the
topic being the science behind the GMO debate. I was chosen largely
because the radio station wanted an academic from Delaware who does plant
genetic engineering (Delaware's a pretty small state, not a lot of
choices), not because I am any sort of acknowledged expert on the issues
surrounding GMO's. Although the conversation was actually fairly balanced
and stuck pretty well to the topic, the Greenpeace speaker cited a fact I
wasn't sure about. He stated that studies have shown that herbicide use by
American farmers is significantly greater on fields planted with
herbicide-tolerant crops than on those planted with non-transgenic crops.
I have seen in previous postings to this list a citation of a study citing
that total use of agrichemicals has gone down. This isn't precisely the
same issue. Is anyone familiar with the studies the Greenpeace
representative cited? Was his information accurate?
Thanks for the info.
Charles Benbrook CU FQPA site www.ecologic-ipm.com
Benbrook Consulting Services Ag BioTech InfoNet www.biotech-info.net
5085 Upper Pack River Road IPM site www.pmac.net
Sandpoint, Idaho 83864
208-263-5236 (Voice) 208-263-7342 (Fax)
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